In the previous article we looked at alternative timeline dinosaurs, and in particular at Dougal Dixon’s The New Dinosaurs, at the Speculative Dinosaur project, and at a few things that connect these two endeavours.
We finished that article by introducing an idea mentioned or discussed several times in discussions about SpecZoo: given that mammal evolution would surely continue in a dinosaur-dominated, post-Cretaceous world, could big-bodied mammals evolve, and could they give rise to humans... or, at least, to human-like primates?
Before I continue, I should add that this issue is especially topical at the time of writing (early December 2019) since a BBC World Service radio programme featuring this very issue has just appeared. It’s part of the CrowdScience series, is titled ‘Would humans exist if dinosaurs were still alive?’ and can be found here. It features me, Memo Kosemen, Elsa Panciroli, Anjali Goswami and Nicola Clayton.
Caption: a whole radio show on speculative dinosaurs! You need a BBC account to access it. Image: BBC (from here).
Could there be humans? Well, this would require the (mostly) terrestrial evolution of a big-bodied primate group, and I said in the previous article (where I called it the no megamammals rule) that that might not be possible in a dinosaur-dominated world (and I mean because dinosaurs and other archosaur groups were filling up the available niche space, not because predatory species were perpetual eliminators of animals that dared set foot on the ground or anything like that). Could, then, we have hypothetical ‘human-level’ apes (thinking here of cultural and technological sophistication, and/or relative intelligence) evolve in an arboreal setting?
Here it’s worth saying that the existence of hypothetical climbing and flying predatory archosaurs might not be an evolutionary obstacle to the existence of relatively big arboreal mammals. I say this because large, scansorial and arboreal mammals have already evolved in a world where they’re predated upon by large, predatory flying theropods, some of which can reach into cavities with flexible legs and feet, or pull relatively big prey items (like sloths and big monkeys) from treetops and branches.
But… if I let my archosaur bias run away with me, I might propose that the existence of arboreal mammals in a dinosaur-dominated world could encourage the evolution of specialised scansorial or arboreal archosaurs (presumably theropods) that have somehow influenced primate evolution, and ultimately derailed any potential evolution of proto-humans. I like this idea, and it isn’t entirely without precedent in our own timeline, since it’s been formally suggested that the predation pressure exerted upon primates by large predatory reptiles – snakes, specifically – has indeed shaped primate evolution (Isbell 2006).
Caption: a speculative arboreal maniraptoran from an alternative timeline. It runs and leaps about in tropical tree-tops, has extremely powerful, prehensile feet, and predates on primate-like mammals. Image: Darren Naish.
Here’s another possibility: could human-like apes evolve on an island refugium where archosaurs weren’t dominant? The idea that ‘unusual’ animals can evolve and persist on islands is already a mainstay of island biogeography theory and verified by many real-world examples. A dinosaur-dominated post-Cretaceous world must be allowed to include similar diversity, and maybe this is where you find your big, atypical mammals (and perhaps big tortoises, arthropods and whatever else).
Could human-like primates evolve on islands? Well, this would require that your ancestral primates occurred in such places in the first place, and that the relevant selection pressures would have led to the evolution of human-like animals. While this isn’t impossible, it seems unlikely: there are good reasons for thinking that the ecological conditions specific to certain regions of Neogene continental Africa are what ultimately resulted in the emergence of hominins and hence humans (Kingdon 2003). My conclusion here is that an alternative evolutionary pathway for primates doesn’t give you humans as one of its ‘products’.
Finally, if we have an alternative timeline where apes evolve, is it conceivable that human-like primates, and, ultimately, alternative timeline humans, evolve anyway, dinosaurs or not? After all, humans and human ancestors spent their entire history living alongside formidable predators and competitors which either had to be avoided, defeated or out-smarted, and we might argue that the technological and other behavioural sophistications of hominids could make them exempt from the ‘no megamammal rule’ introduced above. The result would be what I’m going to call a Flintstones Universe.
Caption: non-bird dinosaurs and humans live alongside one another in the episode In Dino Veritas (season 2, ep 7) of the TV series Sliders, which aired in April 1996.
As appealing as this model might be for the purposes of human-oriented drama and adventure (it’s been done before, in Sliders - a TV series about travel between alternative timeline versions of Earth - and I’m sure elsewhere), I’m worried, since it also sounds a lot like the ‘inevitable humans’ model promoted by those who seem to regard humans as The Best Animals. Some of you might have seen the 2010 episode of the BBC TV series Horizon (it’s here) where Simon Conway Morris – who’s well known, these days, as something of an opponent to the late Stephen Jay Gould’s argument that nothing in evolution is inevitable and that events wouldn’t have run the way they did if we were to “replay life’s tape”* (Gould 1990, p. 48) – proposed both that humans could well have evolved in a dinosaur-dominated world and that smart humanoid dinosaurs could well have evolved as well. Even better, Conway Morris suggests in the same TV show that humans and big-brained dinosaurs could have forged an alliance. True, true, symbiosis is not uncommon in the living world – ants and aphids, cleaner fishes and big reef fishes, Godzilla and Mothra – but the real-world history of humans shows either that we smashed competitors into bloody fragments or absorbed them into our collective via sexy, sexy ways. The latter option is unlikely to play out in a world where humans and humanoid dinosaurs live together, but the former suggests a less than happy outcome for one of the players.
Caption: some of the key books relevant to the discussion here.
So, excuse me if I’m a little sceptical of any proposed human-dinosauroid buddy-flick partnership. And am I sceptical of the idea that hominids, hominines and hominins were indeed exempt of the ‘no megamammals rule’? Yes. Incidentally, Conway Morris’s inevitability vs Gould’s contingency formed the subject of a long-running dispute: Riley Black wrote about this discussion here.
* Does this analogy still work given that hardly anyone uses recording tape anymore?
Caption: Simon Conway Morris talks about the evolution of intelligence while a dinosauroid reads a newspaper in the background. This is a screengrab from the 2007 episode of BBC Horizon titled My Pet Dinosaur.
Other, more recent alternative timeline dinosaur thoughts. As should be clear from this article and its predecessor, interest in alternative timeline dinosaurs is at an all-time high. The current resurgence of monster movies that feature King Kong, Godzilla and the like also means that such creatures have appeared in big-budget, mainstream movies. Peter Jackson’s 2005 movie King Kong featured several post-Cretaceous dinosaurs (among them Vastatosaurus rex, Brontosaurus baxteri and Venatosaurus saevidicus), the design and backstory of which makes at least some sense on the basis of things that happened in the real timeline… though the idea of a dinosaur genus persisting relatively unchanged for 150 million years or so can’t be considered sensible in view of what we know.
Caption: I don’t especially like the dinosaurs of Jackson’s King Kong (they’re too conservative), but a lot of the artwork is neat. This concept art depicts Vastatosaurus rex, a giant Holocene tyrannosaurid that evolved from Tyrannosaurus. Image: The World of Kong (here).
Pixar’s 2015 The Good Dinosaur also has to be mentioned, but I wish it didn’t because I think it’s a terrible film and an abhorrent waste of an opportunity. It’s supposed to be an alternative timeline movie but instead it just seems like a Flintstones reboot without the Flintstones.
Caption: opening spread from Pickrell (2017), art by James Gilleard. Some of the creatures here are based on those of TND and the Speculative Dinosaur Project. Image: BBC Focus magazine.
A 2017 article by John Pickrell is one of the newest published pieces on alternative timeline dinosaurs, and it’s well worth tracking down for those seriously interested in this stuff (Pickrell 2017: there’s an online version here which includes some extra stuff relative to the printed one). It features some fairly outré artwork (by James Gilleard; it’s not included in the online version) depicting creatures inspired by those of The New Dinosaurs, and include quotes from Steve Brusatte, Tom Holtz, Andrew Farke, Matthew Bonnan and Victoria Arbour (and Paul Barrett and me, but in the online version only) (Pickrell 2017).
Caption: the Gourmand Ganeosaurus tardus, a carrion-feeding tyrannosaur whose ancestors migrated to South America during an alt-timeline version of the Great American Biotic Interchange. I’ve never been able to figure out what it’s eating. Image: art by Steve Holden, from Dixon (1988).
A few interesting, specific speculations are made in John’s article. Tom notes that the Gourmand of TND is maybe not so ridiculous given recent discoveries concerning abelisaurs (rather than tyrannosaurs), Matthew suggests that arboreal (non-bird) dinosaurs might have co-evolved with flowering plants, and Victoria proposes that the neornithine bird radiation might not have been as bushy and explosive if pterosaurs had never died out (Pickrell 2017). Other ideas mooted in the article are that climbing, monkey-like theropods might evolve, and that there might be shaggy-coated Arctic specialists, speedy grassland herbivores and whale-like descendants of spinosaurs; in part, they’re seemingly inspired by the Dixonian creatures of TND.
Caption: more art from Pickrell (2017), by James Gilleard. Image: BBC Focus magazine.
The online version of the article includes comments on some of the events of post-Cretaceous times that – if they happened in an alternative timeline – would likely have some impact on the evolution of dinosaurs, pterosaurs and so on. Examples: what would the Paleocene-Eocene thermal maximum mean for dinosaurs, how might dinosaurs and pterosaurs respond to the cooling and drying of the Miocene, the spread of grasslands and so on, and what might happen in the cool, dry conditions of the Pleistocene? There’s vast scope for speculation here and even for some actual science, since we have enough data to show that organisms evolve in predictable directions when faced with increasing or decreasing temperatures and other such changes.
It's at this point that I have to stop – but there’s more to come. The next article (last in this series) covers ‘dinosauroids’ and other hypothetical big-brained dinosaurs.
For previous TetZoo articles on alternative timeline dinosaurs and related issues of SpecZoo, see…
Dinosauroids revisited, November 2006
Dinosauroid cave art discovered, March 2007
How intelligent dinosaurs conquered the world, March 2008
Come back Lank, (nearly) all is forgiven, September 2008
Belatedly, Nemoramjetia (= Avisapiens), November 2008
Richard Dawkins and the crappy 'humanoid dinosaurs' that just won't die, November 2009
Dinosauroids revisited, revisited, October 2012
Of After Man, The New Dinosaurs and Greenworld: an interview with Dougal Dixon, April 2014
Speculative Zoology, a Discussion, June 2018
Could We Domesticate (Non-Bird) Dinosaurs?, August 2018
The Dougal Dixon After Man Event of September 2018, September 2018
TetZoo Bookshelf, February 2019, Part 1, February 2019
Alternative Timeline Dinosaurs, the View From 2019 (Part 1), December 2019
Refs - -
Dixon, D. 1988. The New Dinosaurs: An Alternative Evolution. Salem House Publishers, Topsfield, MA.
Isbell, L. A. 2006. Snakes as agents of evolutionary change in primate brain. Journal of Human Evolution 51, 1-35.
Pickrell, J. 2017. What if the dinosaurs had survived? In Bennett, D. (ed) Dinosaurs: the Ultimate Guide to the Prehistoric Beasts. Immediate Media, Bristol, pp. 74-83.
